Old Painless· Does not know Everything !
Discussion Starter · #1 ·
Anybody had one made to match the engine characteristics with a 160 kit fitted ?
I was going to suggest using the formulae, but there's still a bit of guesswork that's needed afterwards. Im not sure what it would cost either, could be cheap, could stab you in the wallet.macdizzy
read above, get hold of programs, measure polini kit, decide on desired power characteristics, make pipe.
Or buy A. Graham Bell's book "two-stroke performance tuning" as it has the formulars.
swarbricks are still going,i belive that mick abbey has retired(possibly due to ill health) and pete gibson retired at least a couple of years ago,he has passed the gibson name and business to tony and derren at stinkwheels in essexmight be woth giving dave swarbrick, mick abbey or peter gibson a tinkle as they will all build exhausts for ya.
Hi !Any more info on that odd sounding part Markus ?
yeah swarbrick is still going, werent 100% sure on mick abbey, knew pete gibson was retired but if you search for him on google or something it will bring you to the people who he passed the business onto.swarbricks are still going,i belive that mick abbey has retired(possibly due to ill health) and pete gibson retired at least a couple of years ago,he has passed the gibson name and business to tony and derren at stinkwheels in essex
A. Graham Bell's book "two-stroke performance tuning" as it has the formulars.
Coupled with... http://www.prestwich.ndirect.co.uk/tunedpipetheory2.htmWhen using the formulas above for designing or calculating what parameters the pipe to buy should have, the first step is to calculate D1. When you calculate D1 with the D1 formula above, remember that the number is in sq-in and must be converted to the diameter of the header pipe. Do this by dividing your calculation by Pi and then taking the square root. This will give you the radius of the header. Just multiply it by 2 to get the diameter. What you are doing is working the formula for the area of a circle backwards (Area of a circle = Pi r^2). From this point on, no other conversion should be necessary unless you use metric (Multiply numerator of LT formula by 83.3 and use 518.16 m/s for VS to get mm instead of inches) instead of English..... SNIP .....Now comes the fun part! We get to go to the track again, unless of course we have our very own dyno. Not! So we have set the pipe up so that we have an optimum length. Well take it off! That's right, take it off. First we want to get the right prop, right fuel and right needle before we even mess with that pipe. You see this is where the "What a pipe can't do?" comes in. A pipe cannot make up for poor engine setups and crappy gear ratios. A pipe also cannot make up for bad engine timing and some engines are timed so poorly that no pipe will increase performance.
Ok, we make a few (2-3) passes without the pipe. We have the right gear ratio, the right needle setting and this is the fuel we are going to be racing with. Put the pipe back on richen the needle a little and make a run. We pay close attention to what the engine is doing. If the engine turns slower, something is wrong. If the mixture is correct the pipe is too long. Shorten it by 1/8" at a time until the revs start to rise (this can be done at the exhaust coupler). If the pipe is too short the motor will run harshly and the needle setting will be unstable and critical. Add 1/8" to the length at a time (again, at the coupler). When the pipe is at the proper length you will experience the thrill of a lifetime. You will hear the engine and pipe become one in resonance.